The Great Wall of China is not visible from space.
Why it is true
Contrary to myth, the structure is too narrow to be seen from low Earth orbit without optical aid.
Source: NASA
Would you rather be asked first?
This is the reading side of the site, so the answer is in the sentence above — that is the whole point of it. Test yourself works the other way round: the question comes on its own, and the fact and the explanation only appear once you have answered.